These triangles are similar so how do i solve for x?

What is the equation of the graph below? y=sec(x)-4

Multiply. write your answer in simplest form. 3/8 x 5/7

To solve the system of equations below, grace isolated the variable y in the first equation and then substituted into the second equation. what was the resulting equation? 3y=12x x^2/4+y^2/9=1